[1] San Francisco Clin Res Ctr, San Francisco Headache Clin, San Francisco, CA 94109 USA
[2] Thomas Jefferson Univ, Philadelphia, PA 19107 USA
[3] Michigan Head Pain & Neurol Inst, Ann Arbor, MI USA
[4] Elkind Headache Ctr, Mt Vernon, NY USA
[5] Ryan Headache Ctr, Chesterfield, MO USA
[6] UMDNJ, Sch Osteopath Med, Moorestown, NJ USA
[7] Bristol Myers Squibb Co, Plainsboro, NJ USA